Iceland

At least half of the world’s killer whale populations are doomed to extinction due to toxic and persistent pollution of the oceans, according to a major new study.

Although the poisonous chemicals, PCBs, have been banned for decades, they are still leaking into the seas. They become concentrated up the food chain; as a result, killer whales, the top predators, are the most contaminated animals on the planet. Worse, their fat-rich milk passes on very high doses to their newborn calves.

PCB concentrations found in killer whales can be 100 times safe levels and severely damage reproductive organs, cause cancer and damage the immune system. The new research analysed the prospects for killer whale populations over the next century and found those offshore from industrialised nations could vanish as soon as 30-50 years.

Among those most at risk are the UK’s last pod, where a recent death revealed one of the highest PCB levels ever recorded. Others off Gibraltar, Japan and Brazil and in the north-east Pacific are also in great danger. Killer whales are one of the most widespread mammals on earth but have already been lost in the North Sea, around Spain and many other places.

“It is like a killer whale apocalypse,” said Paul Jepson at the Zoological Society of London, part of the international research team behind the new study. “Even in a pristine condition they are very slow to reproduce.” Healthy killer whales take 20 years to reach peak sexual maturity and 18 months to gestate a calf.

PCBs were used around the world since the 1930s in electrical components, plastics and paints but their toxicity has been known for 50 years. They were banned by nations in the 1970s and 1980s but 80% of the 1m tonnes produced have yet to be destroyed and are still leaking into the seas from landfills and other sources.

The international Stockholm Convention on Persistent Organic Pollutants came into force in 2004 to tackle the issue, but Jepson said the clean-up is way behind schedule. “I think the Stockholm Convention is failing,” he said. “The only area where I am optimistic is the US. They alone produced 50% of all PCBs, but they have been getting PCB levels down consistently for decades. All we have done in Europe is ban them and then hope they go away.”

The researchers said PCBs are just one pollutant found in killer whales, with “a long list of additional known and as yet unmeasured contaminants present”. Further problems for killer whales include the loss of key prey species such as tuna and sharks to overfishing and also growing underwater noise pollution.

The new research, published in the journal Science, examined PCB contamination in 351 killer whales, the largest analysis yet. The scientists then took existing data on how PCBs affect calf survival and immune systems in whales and used this to model how populations will fare in the future. “Populations of Japan, Brazil, Northeast Pacific, Strait of Gibraltar, and the United Kingdom are all tending toward complete collapse,” they concluded.

Lucy Babey, deputy director at conservation group Orca, said: “Our abysmal failures to control chemical pollution ending up in our oceans has caused a killer whale catastrophe on an epic scale. It is essential that requirements to dispose safely of PCBs under the Stockholm Convention are made legally binding at the next meeting in May 2019 to help stop this scandal.” Scientists have previously found “extraordinary” levels of toxic pollution even in the 10km-deep Mariana trench in the Pacific Ocean.

“This new study is a global red alert on the state of our oceans,” said Jennifer Lonsdale, chair of the Wildlife and Countryside Link’s whales group. “If the UK government wants its [proposed] Environment Act to be world-leading, it must set ambitious targets on PCB disposal and protect against further chemical pollution of our waters.”

The research shows that killer whale populations in the high north, off Norway, Iceland, Canada and the Faroes, are far less contaminated due to their distance from major PCB sources. ”The only thing that gives me hope about killer whales in the longer term is, yes, we are going to lose populations all over the industrialised areas, but there are populations that are doing reasonably well in the Arctic,” said Jepson.

If a global clean-up, which would take decades, can be achieved, these populations could eventually repopulate empty regions, he said, noting that killer whales are very intelligent, have strong family bonds and hunt in packs. “It is an incredibly adaptive species – they have been able to [live] from the Arctic to the Antarctic and everywhere in between.”

He praised the billion-dollar “superfund” clean-ups in the US, such as in the Hudson River and Puget Sound, where the polluter has paid most of the costs: “The US is going way beyond the Stockholm Convention because they know how toxic PCBs are.”

The calf was first spotted on 20 November along the Snæfellsnes Peninsula, in Iceland, and is the latest offspring of female SN200 (West Iceland ID number), known in Scotland as 012.

The group of orcas spends the winter in Icelandic waters, while migrating south to Shetland and Scotland in the spring and summer.

In the past, both countries ran separate naming programs resulting in animals that travel between the two countries having two different names, often resulting in confusion when sightings were reported.

The naming contest has been organised by Orca Guardians Iceland, a non-profit killer whale research and conservation organisation based in West Iceland.

Firstly, the public is invited to send in naming suggestions for the calf. Four of these will be selected by an international panel of judges, then the public will have the opportunity to vote on four names and select their favourite, which will then be added to the West Iceland ID catalogue.

Iceland’s killer whale society is more fluid than that of their northeast Pacific peers.

The observation that Icelandic killer whales are fluid in both their choice of prey and their group size surprised researchers studying the whales’ social structure. This behavior, discovered by Sara Tavares of Scotland’s University of St Andrews, was unlike that of the intensively studied killer whales of the northeast Pacific, which have more rigid and hierarchical relationships. There, resident killer whales feed on salmon, stick to relatively small home ranges, and live in stable kinship groups led by a matriarch. In contrast, northeast Pacific transient killer whales are marine mammal specialists that live in small groups and travel over wide ranges. While transients also form family groups, it is not uncommon for individuals to form temporary associations with other transient killer whales. Residents and transients, however, rarely interact.

The findings of Tavares’s team show a much less stable association between Icelandic killer whales. They found that groups frequently break apart and come back together, and that it’s not just the prey type, but how the prey act that may be driving their relationships.

Tavares and her team have tracked Icelandic killer whales from boats, photographing the animals as they fed on spawning herring. The researchers amassed nearly 30,000 photographs. From these they were able to identify 314 individuals, and measured the associations of 198 whales, calculating who went where and who spent time with whom.

“One of the most interesting things that we noticed was that individuals with different movement patterns still associated together,” says Tavares. Some whales stay in Iceland year-round, for instance, while some only show up in the summer or winter. Others will travel hundreds of kilometers away to feed on mammals. But on the main herring feeding grounds in Iceland, they will all interact, sometimes in mega pods of dozens, or even a few hundred animals.

So why are Icelandic killer whale societies so much more flexible than those of their northeast Pacific counterparts? Tavares suggests it is because of differences in how their prey behave.

Menopause is a mystery to evolutionary biologists, but new insights could come from a long-term study of killer whales.

In these whales, the explanation may lie in a combination of conflict and cooperation between older and younger females, according to a report published Thursday in the journal Current Biology.

Killer whales are one of only three species known to have menopause — the others are pilot whales and humans. Researchers have long wondered why it was that these few species evolved to have females that spend so much of their lives unable to have babies.

Killer whales start reproducing around age 15, but stop having calves in their 30s or 40s, even though they can live for around a century.

A team led by behavioral ecologist Darren Croft of the University of Exeter decided to search for answers with the help of an unusual long-term study of killer whales in the Pacific Northwest. There, since the 1970s, researchers have carefully collected information on the births and deaths of individual whales that live in family groups.

Contained within the data is an intriguing clue about why female whales may stop reproducing later in life.

When older females reproduce at the same time as their daughters, who live alongside them, the calves of the older mothers are nearly twice as likely to die in the first 15 years of life. But when older mothers had calves in the absence of a reproducing daughter, their calves did just fine.

“It’s not that older mothers are bad mothers, that they’re not able to raise their calves as younger mothers,” says Croft. “It’s that when they enter into this competition with their daughters, they lose out and their calves are more likely to die.”

The competition may center on access to food, says Croft, because there’s good reason to believe older females feel more pressure to share their precious fish with the others around them.

That’s because, in killer whales, females mate with males from other groups but then rejoin their families. That means when a new calf is born, its father is not around, and females start their lives in a situation where their relatedness to the group is rather low.

As a female grows older and starts having calves that stay with her, however, she develops more kinship ties to those around her. “It may be that older females are more likely to share, and younger females are less likely to share food,” says Croft. That would mean younger females would have more resources to lavish on their own calves.

It’s clear that in these whales, older females play an important role in the survival of not just their own calves, but all of the family members they live with. “If an old female dies, her son’s risk of dying in the year following her death is over eight times higher than if his mother was still alive,” says Croft, “and these are adult sons, these are not juveniles, these are 30-year-old, fully grown males.”

The idea that older females safeguard and enhance their genetic legacy by protecting and providing for their children and grandchildren has been an influential explanation for why menopause evolved. It’s known as the Grandmother hypothesis, and was developed by anthropologists who studied hunter-gatherer cultures.

But Croft thinks that alone isn’t enough to account for menopause, because other long-lived, social species, like elephants, have older females that help their group but continue to bear young until the end of life. “Just the fact that these old females can store information and share that with the group and increase their survival doesn’t explain why they stop reproducing,” says Croft.

Proponents of the Grandmother hypothesis, however, may not be so convinced that intrafamilial conflict plays an important role.

Anthropologist Kristen Hawkes, at the University of Utah, says the killer whales are fascinating, but that they’re hard to study. “They’re doing all kinds of stuff where you can’t see it, and even to get demographic data is just so tricky, because they’re all underwater and they’re long-lived,” she says.

She points to one recent study on food-sharing in killer whales that found older females share fish with their older adult sons, perhaps to maximize the males’ ability to sire more babies.

If that’s the case, she says, “it’s not the older females and younger females in competition, it’s the older females contributing to the enormous success of their sons, and then those baby whales are all born somewhere else. They’re not competing, because their moms are elsewhere.”

A POD of six killer whales from Iceland has been spotted in the Moray Firth.

The animals were photographed by a local boat trip crew near Covesea on Monday, marking the most southerly point off Scotland’s east coast where Icelandic orcas have ever been seen.

At least three of the animals, which are members of the dolphin family rather than whales, were individuals known to conservationists. The unexpected appearance occurred during the annual Orca Watch, organised by the research charity Sea Watch Foundation (SWF).

The operation is carefully planned to coincide with the arrival of killer whales in the Pentland Firth and allows the team to collect data about orcas and other cetaceans that visit these northerly waters.

However, the Icelandic pod surfaced more than 60 miles to the south of the strait that divides Orkney from mainland Scotland, witnessed by SWF’s Alan Airey.

The surprise occurrence sparked a huge response on social media, with representatives of the Icelandic Orca Project confirming that three of the animals had been officially catalogued there.

Killer whales can be seen in several locations around Scotland. Those seen off northern and eastern coasts are migratory, following mackerel and herring shoals.

On the other side of the country is a small group of nine animals that are resident all year round. Known as the West Coast Community, they do not interact with the migratory pods and have never produced any offspring.

“Although this sighting is now the furthest south that individuals from the Icelandic population have been confirmed, other killer whale sightings have occurred in the Moray Firth and further south on many occasions,” said SWF sighting officer Kathy James.

SWF founder and director Dr Peter Evans added: “Members of a pod that has numbered up to 14 can be seen annually around the Hebrides of west Scotland, mainly in summer.

“The most famous of these is a mature male nicknamed John Coe that we have observed since at least 1980. It has a distinct nick towards the base of the dorsal fin, making it instantly recognisable, and a chunk out of its tail – possibly a shark bite. Sightings of John Coe have ranged from the Hebrides over to East Scotland, south to the northwest coast of Ireland and well into the Irish Sea off west Wales.”